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Date: Wed, 23 Aug 2023 07:37:43 -0700
From: Rita Zhang <>
Subject: [kubernetes] CVE-2023-3893: Insufficient input sanitization on
 kubernetes-csi-proxy leads to privilege escalation

Hello Kubernetes Community,

A security issue was discovered in Kubernetes where a user that can create
pods on Windows nodes running kubernetes-csi-proxy may be able to escalate
to admin privileges on those nodes. Kubernetes clusters are only affected
if they include Windows nodes running kubernetes-csi-proxy.

This issue has been rated ***HIGH*** (
and assigned **CVE-2023-3893**

*Am I vulnerable?*

Any kubernetes environment with Windows nodes that are running
kubernetes-csi-proxy is impacted.  This is a common default configuration
on Windows nodes.  Run `kubectl get nodes -l`
<> to see if any Windows nodes are in use.

*Affected Versions*

- kubernetes-csi-proxy <= v2.0.0-alpha.0

- kubernetes-csi-proxy <= v1.1.2

*How do I mitigate this vulnerability?*

The provided patch fully mitigates the vulnerability and has no known side
effects.  Full mitigation for this class of issues requires patches applied
for CVE-2023-3676, CVE-2023-3955, and CVE-2023-3893.

Outside of applying the provided patch, there are no known mitigations to
this vulnerability.

*Fixed Versions*

- kubernetes-csi-proxy v2.0.0-alpha.1

- kubernetes-csi-proxy v1.1.3

These releases will be published over the course of today, August 23rd,

To upgrade: cordon the node, stop the associated Windows service, replace
the csi-proxy.exe binary, restart the associated Windows service, and
un-cordon the node.  See the installation docs for more details:

If a Windows host process daemon set is used to run kubernetes-csi-proxy
such as,
simply upgrade the image to a fixed version such as


Kubernetes audit logs can be used to detect if this vulnerability is being
exploited. Pod create events with embedded powershell commands are a strong
indication of exploitation.

If you find evidence that this vulnerability has been exploited, please

*Additional Details*

See the GitHub issue for more details:


This vulnerability was discovered by James Sturtevant @jsturtevant and Mark
Rossetti @marosset during the process of fixing CVE-2023-3676 (that
original CVE was reported by Tomer Peled @tomerpeled92)

The issue was fixed and coordinated by the fix team:

James Sturtevant @jsturtevant

Mark Rossetti @marosset

Andy Zhang @andyzhangx

Justin Terry @jterry75

Kulwant Singh @KlwntSingh

Micah Hausler @micahhausler

Rita Zhang @ritazh

and release managers:

Mauricio Poppe @mauriciopoppe

Thank You,

Rita Zhang on behalf of the Kubernetes Security Response Committee

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